Generally, as braking control executed when a vehicle driver operates a brake pedal, assist control is known that assists the increasing of a braking force applied to wheels based on the operation of the brake pedal by the driver (for example, patent documents 1 and 2). Such assist control is executed when it is determined that a highly urgent braking operation has been performed. The assist control is also referred to as “brake assist control (BA control)”.
A highly skilled driver who is good at driving vehicles can adjust the operating manner of the brake pedal as necessary. For example, when emergency braking (sudden braking) is necessary, a highly skilled driver depresses the brake pedal quickly and strongly. In this case, the depression amount and the depression speed of the brake pedal are sufficient, so that the assist control does not need to be executed.
Accordingly, the braking control device disclosed in patent document 3 determines that the depression force applied to a brake pedal by a driver is large when the depression amount of the brake pedal is greater than or equal to a first depression amount and the depression speed of the brake pedal is greater than or equal to a first depression speed. When the depression force applied to the brake pedal is determined to be large, the assist control is not performed. Typically, the brake pedal depression amount and speed are calculated by using a pressure sensor (also referred to as an MC pressure sensor) for detecting the pressure in a master cylinder, which generates liquid pressure in accordance with the manner in which the driver operates the brake pedal.